In today's transport networks, telecommunications data may be transported using time division multiplexing (TDM) or packet forwarding. In TDM, data may be divided into a bit stream that is transferred at a constant bit rate and reassembled at the destination. In contrast, packet-based networks divide the data into frames or packets and transport the frames or packets at various rate. One aspect of transport networks is to tolerate network failures, a characteristic that is often referred to as a network availability enhancement. Such failures may be caused by faults in the physical links of the network or due to hardware or software failures in any of the components of the network. Network availability enhancements can be implemented using several techniques that have been established and standardized for TDM-based transport networks. These techniques generally detect a transport network failure, notify the transport channel end point, and then switch the bit stream to another pre-provisioned or backup channel.
Unfortunately, although the TDM-based enhancement availability techniques can be implemented in packet transport networks (PTNs), they do not take advantage of packet transport characteristics. Thus, an improved network availability enhancement for PTNs that can be implemented in real-time is possible.